updated 10:43 am EDT, Mon September 9, 2013

Failure to update could cause users to lose books after iOS 7 upgrade

In an unusual move, Amazon has released what it calls a "required" update -- v3.9.2 -- for the Kindle iOS app. The company warns that without the update, installing iOS 7 on a device could force people to have to re-register in the app, and re-download any saved books. It's unexplained why iOS 7 would cause the personal data to be lost.

Apple is expected to announced iOS 7's release date during its September 10th iPhone event. The firmware will likely go live around the same time, or within a matter of days, making it urgent for developers to get any critical app updates out to the public. Another wave of app updates will likely hit after September 20th, when the iPhone 5S and 5C are expected to be released and developers will be able to take advantage of new hardware features.